Virtual file server

ABSTRACT

The present disclosure provides a method and a system for migrating a virtual file server. In an example of a method, a virtual file server is migrated from a first storage to a second storage, wherein the virtual file server comprises a server layer and a data layer. Identity information is retrieved from the server layer from the server layer for the second storage. The identity information is updated so instantiation of the virtual file server on the second storage appears the same as on the first storage.

BACKGROUND

A file system is used in computing for controlling the storage andretrieval of data. In particular, file systems are used to identify andseparate data into individual units, and each unit is considered a“file” of the system. The overall file system is the logic and structureused to locate, store, retrieve, and manage groups of information orfiles. A file server can be a computer used to provide the location forshared disk access, which is the shared storage of computer files, andto enable the retrieval of data while computations are made by computerson the network. A virtual file server consists of a virtualized deviceconfigured to store any means of computer files and information. Thesecomputer systems and data identification and retrieval technologies areused throughout many different businesses and for a myriad ofapplications.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain examples are described in the following detailed description andin reference to the drawings, in which:

FIG. 1 is an example block diagram of a computer system for blockreplication, virtualization, and migration of a file server;

FIG. 2 is a block diagram of a storage area on an example file system;

FIG. 3 is a process flow diagram of an example method for creating adetachable file server;

FIG. 4 is a process flow diagram of an example method for migrating adetachable file server between storage arrays; and

FIG. 5 is an example block diagram showing a non-transitory,computer-readable media that holds code that enables the migration of avirtual file server.

DETAILED DESCRIPTION OF SPECIFIC EXAMPLES

In computing, block replication is a technique used to ensureconsistency between resources like hardware and software, and to improvethe sharing and accessibility of information and the reliability thoseprocesses, Server virtualization for computing systems allows softwareto convert a physical server into multiple virtual machines or virtualservers. Through server virtualization, a virtual server acts as aphysical computing device that can run its own operating system.

The concept of multi-tenancy is the use of a single object of softwarethat is run on a server and serves multiple client entities or tenants.The architecture of multitenant applications is configured to partitiondata and configuration information virtually, with each tenant receivingits own virtualized application. A detachable self-contained file serveris described herein that adds to these existing computing techniqueswith new methods. The technology herein combines block and filereplication techniques with concepts from server virtualization tocreate a self-contained file server that can easily migrate from onestorage array to another.

Virtualization of servers and a multitenant architecture saves physicalcomputing space, and can provide more widespread access to information.File servers may provide the location for shared disk access. Achallenge is to provide a file server solution that could providemulti-tenancy features in order to facilitate use, for example, inlarger businesses with centralized information technology resourcesserving many departments, or a in a service provider environment for acloud file server solution. A virtualization for a layered solutionleveraging server can be used to provide a tenant container where eachtenant is supported by one or more virtual machines (VMs) serving as agateway to the underlying storage. However, scaling to a larger numberof tenants requires significant computing resources in order to supportthe VMs, especially when there are hundreds or thousands of supportedVMs.

Examples discussed herein provide a low cost and effective disasterrecovery (DR) solution for a file server product. Generally, the filesystem is tightly coupled to the clustering software running on the fileserver gateways, making it necessary to boot the gateways from volumeson the storage arrays and replicate those boot volumes along with theuser data to the second site. In the case of a failover event, a secondset of physical file server gateways is booted off the replicated bootvolumes from the first site, with ownership of the replicated user datatransferred to the second site as well. Some scripts would be run on theservers to adjust for changes in hardware between sites. This leveragesa cluster of physical file server gateways at one site layered on blockstorage, and replicates the data to a second site using blockreplication features of the array. This setup is difficult to maintainand does not practicably scale in a many-to-one replication scenariothat might be found in a remote-office/branch-office use case.

In examples disclosed herein, file services technology are used incombination with block storage technology of storage arrays. Amulti-protocol array can be used to deliver block storage, file storage,and object storage. For block storage, Fibre Channel (FC)/Internet SmallComputer System Interface (iSCSI)/Fibre Channel Over Internet (FCoE)attachment can be utilized. For file storage, Server Message Block(SMB)/Network File System (NFS)/Hypertext Transfer Protocol (HTTP)/FileTransfer Protocol (FTP) over Ethernet can be utilized. The examplesherein provide a DR feature set similar to a remote copy for a storagearray for block storage volumes, but applied to both the file and objectdata of the combined product. Examples provide a solution for fileserver consolidation, file server multi-tenancy, and file serverbusiness continuity.

Some examples described herein implement a method for transparentlymigrating a virtual file server, including replicating blocks of thevirtual file server between a first storage and a second storage,wherein the virtual file server comprises a server layer and a datalayer. The method includes migrating the virtual file server across astorage cluster boundary from the first storage to the second storage.The method includes retrieving identity information from the serverlayer for the second storage. The method also includes updating theidentity information so the instantiation of the virtual file server onthe second storage appears the same as on the first storage.

An example described herein uses a detached data store, including astorage region, to house a virtual file server. The virtual file serverincludes a server layer and a data store layer. The server layerincludes server identity information. The data store layer includes adrive of the storage region. The virtual file server is detachable fromthe storage region, and the virtual file server is migrated to a secondstorage region.

FIG. 1 is an example block diagram of a computer system 100 for blockreplication, virtualization, and migration of a file server. A computerdevice 102 may process and store a file system. The computer device 102may be, for example, a laptop computer, a desktop computer, asmartphone, or a computing tablet, among others. The computer device 102may include a processor 104 that is configured to execute storedinstructions, as well as a memory device 106 that stores instructionsthat are executable by the processor 104, The processor 104 can be asingle core processor, a dual-core processor, a multi-core processor, acomputing cluster, or the like. The processor 104 may be coupled to thememory device 106 by a bus 108 where the bus 108 may be a communicationsystem that transfers data between various components of the computerdevice 102. In embodiments, the bus 108 may be a PCI, ISA, PCI-Express,HyperTransport®, NuBus, or the like.

The memory device 106 can include random access memory (RAM), e.g.,SRAM, DRAM, zero capacitor RAM, eDRAM, EDO RAM, DDR RAM, RRAM, PRAM,read only memory (ROM), e.g., Mask ROM, PROM, EPROM, EEPROM, flashmemory, or any other suitable memory systems. The computer device 100may also include a storage device 110. The storage device 110 mayinclude non-volatile storage devices, such as a solid-state drive, ahard drive, an optical drive, a flash drive, an array of drives, or anycombinations thereof. The storage device 110 may include a number ofmodules configured to provide the computer device 102 with blockreplication and migration functionality. The storage device 110 includesa physical file system 112. The physical file system 112 includes filesystem information used to identify and separate data into individualunits, and includes the logic and structure used to locate, store,retrieve, and manage files. The physical file system 112 includesvirtual file server (VFS) 114. The VFS 114 will configure a name,network address, and authentication mechanism for access to the VFS 114or physical file system 112. The VFS 114 includes server layer 116 anddata layer 118, The server layer 116 is where the concepts of serveridentity are bound, such as name, IP address, and authenticationmechanism, for example. The data layer 118 corresponds to a storagedrive, for example, the C and D drive in a Windows file server. Theconfiguration of file sharing is bound to the data layer 118, and adirectory can be shared at the root or below within the data layer 118.

A network interface controller (NIC) 120 may also be linked to theprocessor 104. The NIC 126 may link the computer device 102 to thenetwork 122 through a physical connection, or through a wirelessconnection. The network 122 can connect to a separate computing device124 through another NIC 126, or a similar network connection. Thenetwork 122 allows the computer device 124 to network with resources,such as the Internet, printers, fax machines, email, instant messagingapplications, and with files located on the other computing device 102,or storage servers 125, for example. Computer device 124 includesprocessor 128, memory 130, and bus 132 that are described as above withrespect to processor 104, memory 106, and bus 108. Computer device 124includes storage 134 to store physical file system 136. The physicalfile system 136 includes a virtual file server (VFS) 138 that is areplica of the VFS 114 on physical file system 112. The VFS 114 can bevirtually detached from computer device 104, migrated to computer device124, and configured as VFS 138. In some examples, the physical filesystem 112 can be disconnected from computer device 102 and moved toanother computer device, e.g., computer device 124 to migrate the VFS114 as VFS 138. The sever layer 140 and data layer 142 of VFS 138correspond to the server layer 116 and data layer 118 of VFS 114. Thevirtualization of the physical file system 112 on VFS 114 and thereplication of the VFS 114 to the VFS 138 on physical file system 136provide a mechanism for disaster recovery (DR) without using dedicatedhardware on standby at the target site.

Another computer device 144 can be connected to computer devices 102 and124 through the network 122 through NIC 146. Computer device 144 caninclude processor 148, memory 150, and bus 152 that are described asabove with respect to processor 104, memory 106, and bus 108. Theprocessor 148 may be connected through the bus 152 to an input/output(I/O) device interface 154 configured to connect the computer device 144to one or more I/O devices 156. The I/O devices 156 may include, forexample, a keyboard, a mouse, or a pointing device, wherein the pointingdevice may include a touchpad or a touchscreen, among others. The I/Odevices 156 may be built-in components of the computer device 144, orlocated externally to the computer device 144. The processor 148 mayalso be linked through the bus 152 to a display interface 158 configuredto connect the computer device 144 to display devices 160. A displaydevice 160 may be a built-in component of the computer device 144, orconnected externally to the computer device 144. The display device 160may also include a display screen of a smartphone, a computing tablet, acomputer monitor, a television, or a projector, among others. Computerdevice 144 also includes storage 162 to store data and instructions. Auser may interact with computer device 144 and configure or initiate theblock replication and virtualization of a file server located on anothercomputer device, for example VFS 114 on a first storage 110 associatedwith computer device 102 is transparently migrated to VFS 138 on asecond storage 134 associated with computer device 124.

The block diagram of FIG. 1 is not intended to indicate that thecomputer system 100 is to include all of the components shown in FIG. 1.Further, any number of additional components may be included within thecomputer system 100, depending on the details of the specificimplementation of the described herein. For example, a virtual machine(VM) can be utilized instead of computer device 144 by a user toconfigure or initiate file server migration. Further, the componentsdiscussed are not limited to the functionalities mentioned, but thefunctions could be done in different places, or by different modules, ifat all,

FIG. 2 is a block diagram of a storage region in an example file system200. The file system 200 is stored by some form of storage, for example,a storage device or storage array. The file system 200 is used to manageaccess to the content of files on the storage, as well as the metadataabout those files. The file system 200 can automatically provision a setof volumes to meet a requested size and create a virtual file server(VFS) 202. A file store (not shown) within the VFS 202 can be created,and one or more shares can be created using SMB/NFS/HTTP of folderswithin the file store.

In some examples, a file system 200 is created based on porting of anADVFS file system from HP-UX to Linux, for example. This can include avolume manager that can aggregate multiple underlying block devices intoa domain. The process of domain discovery allows information about thecontained file systems to be determined and imported into a clusterconfiguration. In some examples, a logical file system can be layered ontop of the physical file system 200, and can be used to implement ascale-out file system. Scale-out storage is a networked-attached storagearchitecture where disk space can be expanded, even if new target drivesexist on a separate storage array. The logical file system providespolicy containers leveraged to store relevant policy information thatdescribed the identity of the VFS 202. Virtualization of file serverspresents a logical space for data storage, and controls the process ofmapping the logical space to the actual physical location of the data.

The VFS 202 includes plugins to implement different pieces offunctionality to manage the system. These plugins include a data policylayer 204, and a server policy layer 206, which are the two primarylayers of policy containers within the file system 200. The VFS 202 caninclude a platform management layer 209 for clustering andmanageability. The platform management layer 209 can provide aninfrastructure for implementing policy and manageability, in addition tomanagement of cluster formation and maintenance. The platform managementlayer 209 is instantiated per file services cluster and is notreplicated across sites, for example, from one array to another.

Instead of capturing the networking, authentication, and file sharingpolicy in a cluster level file store, these policies are now storedwithin the file system itself using the policy containers, Additionalplugins (not shown) can be used to implement value added services suchas, for example, anti-virus, quotas, and snapshots. The services willhave associated policies stored in the VFS 202 on either the data policylayer 204, or the server policy layer 206, and not in a platformmanagement store, or the like. The data policy later 204 corresponds toa C or D drive in a Windows file server, or the like, and is where theconfiguration of file sharing is bound.

The server policy layer 206 includes metadata 208 and authenticationdata 210, and is where concepts of server identity are bound, such asname, IP address, and particular authentication mechanism. By storingthe file sharing information within the server layer 206 rather than ina cluster level file store, the sharing information is automaticallyrecovered when the virtual file server 202 is migrated to a separatestorage cluster.

A feature of the file system 200 of FIG. 2 is to provide a file serversolution that incorporates multi-tenancy features. The inclusion ofefficient multi-tenancy features facilitates use of the currenttechnology in larger companies with centralized IT serving manydepartments, as well as in a service provider environment for a cloudfile server solution, for example. A technology like a 3PAR™ array, forexample, including a VM running on each 3PAR™ controller node can beused to implement the techniques described herein.

A feature leveraged by the file system 200 is the block replication of aVFS 202 between arrays, where options for both synchronous andasynchronous replication are available. Block replication is forreplicating the VFS 202 making up a file system from one array toanother so the file system 200 can be presented to a file servicescluster (not shown) on the remote array without any a priori knowledgeof the file system 200, Another included feature is the creation ofblock snapshots to provide a protection mechanism against corruption ofthe file system 200 that may not be recoverable through file basedsnapshots. Another included feature is technology that allows formigration of VFS 202 transparently from one array to another, Such fileserver migration techniques can be used for cases such as, for example,load balancing, or retirement of an array.

The block diagram of FIG. 2 is not intended to indicate that the filesystem 200 is to include all of the components shown in FIG. 2. Further,any number of additional components may be included within the filesystem 200, depending on the details of the specific implementation ofthe described herein. For example, the components discussed are notlimited to the functionalities mentioned, but the functions could bedone in different places, or by different components, if at all,

FIG. 3 is a process flow diagram of an example method 300 for creating amigratable file server. The method 300 may be implemented, for example,by the computer devices 102, 124 described with respect to FIG. 1. Inparticular, the computer device can be configured to permit the blockreplication, file server virtualization and migration techniques thatare disclosed herein. The method 300 begins at block 302.

At block 302, a virtual file server is moved from a first storage array.The movement of the VFS can be physically performed, for example, bydisconnecting a drive from the first storage array. In some examples,the VFS can be virtually moved by copying of the storage blocks thatmake up the VFS.

A typical file server is a computer attached to a network that is toprovide a location for shared disk access that can be accessed by othercomputers that are attached to the same network. File servers arerelated to storage and management of data, and storage virtualization isto enable better functionality and advanced features within and acrossstorage systems, including a number of disk drives or a disk array.Block virtualization refers to the separation of logical storage fromphysical storage so that logical storage may be accessed without respectto the physical storage or a heterogeneous structure. Virtualization ofstorage can achieve location independence by separating or abstractingthe physical location of the data. For storage that is virtualized,replication is implemented above the software or device that isperforming the virtualization.

At block 304, the virtual file server is migrated to a second storagearray. The migration may be performed by physically connecting a drivethat has been disconnected from a first storage array to a secondstorage array. The migration, as well as the replication, of the virtualfile server contained in this physical file system is transparent sofiles are able to be moved without another client having access to thefiles knowing. The replication and migration of the virtual file serversupports the scalability and multi-tenancy features described herein. Inanother example, the blocks that have been copied from a first storagearray are written into the second storage array.

At block 306, identity information for the virtual file server isretrieved at the second storage array. After being moved or replicatedand before receiving the identity information, the file system isunmounted from the first storage array using the virtual file server andan ownership change for the virtual file server is initiated to give thesecond storage array priority.

At block 308, the identity information is updated at the second storagearray. VMs on storage clusters of the second storage array will detectthe new virtual file servers and read the metadata from the virtual fileservers as part of a domain discovery. Through this domain discovery,basic information about the file system contained on the virtual fileserver will be provided, and a mount operation can be performed on thevirtual file server and file system to the second storage array.

Implementation of method 300 results in a multiprotocol array,delivering FC/iSCSI/FCoE attachment for block storage, SMB/NFS/HTTP/FTPover Ethernet for file storage, and, for example, OpenStack Swift™ (overHTTP), or the like, for object storage. The techniques described hereindeliver a DR feature set similar to that used for block storage volumes,but applied to the file and object data that are being added into thecombined product. The techniques disclosed simplify the DR scenario bydecoupling the file server configuration from the storage cluster thatis hosting the file server. Furthermore, this method 300 and method 400below efficiently allows multi-tenancy without requiring dedicatedcontainers, like a VM, for each tenant, Finally, the techniques hereinfacilitate balancing load across hardware resources by allowing a fileserver to migrate across physical cluster boundaries.

The process flow diagram in FIG. 3 is not intended to indicate that themethod 300 is to include all of the components shown in FIG. 3. Further,the method 300 may include fewer or more steps than what is shown,depending on the details of the specific implementation.

FIG. 4 is a process flow diagram of an example method 400 for migratinga detachable file server between storage arrays. Method 400 embeds fileserver identity into a policy container within a virtual file serverwithin the file system, and makes the file system easily detachable fromthe original host environment for the file system. Block replicationtechniques are able to effectively move, or replicate and migratevirtual file servers between physical hosting environments withoutneeding to worry about replicating an entire operating system, as istypical for previous solutions. The method 400 begins at block 402.

At block 402, a virtual volume set is created and comprised of virtualfile servers within a physical file system. The virtual volume set willautomatically provision to meet a requested size virtual file server ornumber of virtual file servers. At block 404, a share is created using aprotocol within the file system. The protocol is typically related tofile storage and can be, for example, Server Message Block (SMB),(Network File System) NFS, or HTTP. At block 406, the virtual volume setis either physically moved or is replicated from a first storage arrayto a second storage array. Method 400 does not rely on a file systembeing tightly coupled to clustering software running on gateways. Thismethod 400 avoids the possibility of some scripts needing to be run onservers to adjust for issues where the OS was expecting to have one setof hardware attached and instead different hardware was present. It istherefore not necessary to boot the gateways from volumes on the firststorage array and replicate those boot volumes along with the user datato the second storage array, thus permitting the techniques discussedherein to be more efficient and cost effective.

At block 408, the file system is unmounted from the first storage array.The unmount operation of the file system is triggered by the initiationof an ownership change for the virtual volume set so that an array otherthan the host array becomes designated as the primary array. The unmountoperation includes disabling the network addresses owned by the virtualfile server. After the unmount operation completes, an applicationprogramming interface (API) call will be made to remove the record ofthe file server from the platform management store of the first array.This will be done without actually performing any operation on thevirtual volumes. At block 410, the virtual file server is unpresentedfrom a VM running on the first storage array. At this point, the firststorage array is ready to relinquish ownership of the virtual fileserver.

At block 412, the physical file system that spans the virtual fileserver is brought-up on the second storage array. The second storagearray now owns the virtual file server and a storage discovery operationcan be requested and performed. The VMs will detect the new physicalfile system and the virtual file server associated with it and thevirtual volumes therein and read related metadata as part of domaindiscovery, thereby providing basic information about the file systemcontained on the virtual volumes. A request is then made to import thefile system into the cluster, at which point a record of the file systemis made in the platform management store on the second storage array. Atblock 414, a mount operation can now be performed for the file system onthe second storage array.

At block 416, policy information about the virtual file server isretrieved from a policy container in the file system. The policyinformation is retrieved during the mount of the file system on thesecond storage array. At block 418, the network addresses associatedwith the virtual file server on the second storage array are enabled. Atblock 420, the shares are presented over a network interface for useraccess to connected devices throughout the network. A user may configurethe file server replication and migration from a computer device that isunrelated to the first or second storage arrays, and thereby remotelyinitiate the method 400 described herein. From the perspective of theclient of the file server, the instantiation of the virtual file serveron the second storage array looks the same as it did on the firststorage array.

The process flow diagram in FIG. 4 is not intended to indicate that themethod 400 is to include all of the components shown in FIG. 4. Further,the method 400 may include fewer or more steps than what is shown,depending on the details of the specific implementation.

FIG. 5 is an example block diagram showing a non-transitory,computer-readable media 500 that holds code to enable file servervirtualization and migration. The computer-readable media 500 may beaccessed by a processor 502 over a system bus 504. The code may directthe processor 502 to perform the steps of the current method asdescribed with respect to FIGS. 3 and 4. For example, the VFS 202,including data layer 204 and server layer 206, described as above withrespect to FIG. 2, can be stored on the computer-readable media 500. TheVFS 202 is configured to be migrated from computer-readable media 500 tosome other storage, such as a storage array or storage cluster.

A block replication module 506 is configured to provide synchronous orasynchronous replication between storage arrays for virtual volumes,which make up a file system, and ultimately VFS 202. The blockreplication module 506 allows the file system to be presented to a fileservice cluster on a remote storage array without the array having apriori knowledge of the file system. The concept of the file serveridentity is embedded into a policy container of the VFS 202,specifically the server layer 206 within the file system and the filesystem itself, is then easily separable from the host environment. Theblock replication module 506, along with the migration module 508, allowa set of VFS 202 to migrate between physical hosting environmentswithout the need to replicate an entire boot drive or operating system,and while still providing an effective DR solution for a file serverproduct.

The migration module 508 transparently migrates the VFS 202 so files areable to be moved over the network without another client device, of aplurality of client devices, knowing. The replication and migration ofthe virtual file server supports multi-tenancy without the need for eachtenant being supported by its own VM. The migration module 508 is toinitiate an ownership change for a VFS 202, designating a second storageas primary. The migration module 506 allows the VFS 202 to unmount froma host storage. The migration module 506 can remove the record of thefile system from the host storage without modification of virtualvolumes or the VFS 202. The migration module 508 is also to present thenewly owned VFS 202 to VMs on the second storage. The VMs will detectthe new VFS 202 and read the metadata from the VFS 202, thereby allowingthe VMs to access the underlying file system associated with the VFS202. The migration module 508 is also to import the file system to thesecond storage, and make a record of the file system on a platformmanagement store of the second storage. The migration module 508ultimately mounts the file system through the virtual file server to thesecond storage.

An identity update module 510 is configured to complete the mount of thefile system on the second storage by, for example, retrieving policyinformation from the server layer 206 of the VFS 202. Network addressesassociated with the file system are enabled by the identity updatemodule 510. Shares are then presented over various network interfacesfor user data access throughout a network. The identity update module510, as well as the block replication module 506 and migration module508, are to operate transparently to client devices on the network, suchthat instantiation of the VFS 202 on the second storage appears the sameas on the host storage environment.

The block diagram of FIG. 5 is not intended to indicate that thecomputer-readable media 500 is to include all of the components ormodules shown in FIG. 5. Further, any number of additional componentsmay be included within the computer-readable media 500, depending on thedetails of the specific implementation of the file server virtualizationand migration techniques described herein.

While the present techniques may be susceptible to various modificationsand alternative forms, the exemplary examples discussed above have beenshown only by way of example. It is to be understood that the techniqueis not intended to be limited to the particular examples disclosedherein. Indeed, the present techniques include all alternatives,modifications, and equivalents falling within the true spirit and scopeof the present techniques.

What is claimed is:
 1. A method for transparently migrating a virtualfile server, comprising: migrating a virtual file server between a firststorage and a second storage, wherein the virtual file server comprisesa server layer and a data layer; retrieving identity information fromthe server layer for the second storage; and updating the identityinformation so instantiation of the virtual file server on the secondstorage appears the same as on the first storage.
 2. The method of claim1, wherein migrating the virtual file server is performed by: detachinga physical file system that comprises the virtual file server from thefirst storage; and attaching the physical file system to the secondstorage.
 3. The method of claim 1, wherein migrating the file server isperformed by replicating blocks of the virtual file server from thefirst storage to the second storage.
 4. The method of claim 1, whereinmigrating the file server is performed transparently to a client of aplurality of clients on a network.
 5. The method of claim 1, comprisingretrieving metadata and authentication information from the virtual fileserver.
 6. The method of claim 1, comprising binding file sharing to adrive level.
 7. The method of claim 1, wherein migrating the file servercomprises configuring for load balancing between storage arrays.
 8. Themethod of claim 1, comprising creating block snapshots.
 9. A detachabledata store, comprising a storage region, comprising: a virtual fileserver, wherein the virtual file server is comprised of a server layerand a data store layer; wherein the server layer comprises serveridentity information; wherein the data store layer comprises a datalevel of the storage region; and wherein the virtual file servercomprised code that automatically instantiates the virtual file serverwhen the detachable data store is coupled to a storage system.
 10. Thedetached data store of claim 9, wherein the detachable data store isconfigured to be detached from a first storage array and attached to asecond storage array, and wherein the detachable data store isconfigured to automatically instantiate on the second storage array. 11.The detachable data store of claim 9, wherein the server identityinformation from the server layer comprises metadata and authenticationinformation.
 12. The detachable data store of claim 11, wherein themetadata comprises the information about the location of files andaccess information, and wherein the access information includes a typeof drive, a list of drives, a list of users with access, or anycombination thereof.
 13. The detachable data store of claim 9, wherein aconfiguration for file sharing is bound to the drive level of thestorage region.
 14. A non-transitory, machine-readable medium comprisinginstructions that when executed by a processor cause the processor to:activate a virtual file server that has been disconnected from a firststorage array and connected to a second storage array; retrieve identityinformation from a server layer in the virtual file server; and updatethe identity information to make instantiation of the virtual fileserver on the second storage array appears the same as on the firststorage array.
 15. The non-transitory, machine-readable medium of claim14, further comprising instructions that when executed by a processorcause the processor to migrate the virtual file server by replicatingblocks associated with the virtual file server from the first storagearray to the second storage array.